1. Field of the Invention
The present invention relates to a tube cutter and especially to a tube cutter having a relative movement generating portion. It can quickly clamp on a pipe. It can avoid over-applying force. It can automatically feed in and cut it. And, it utilizes the design of hand-clamping method for feeding the blade.
2. Description of the Prior Art
One typical traditional mini-tube cutter (such as the PCT Patent Pub. No. WO 02/02264) can be seen in FIG. 1. When a user wants to cut the pipe 91, the user must rotate a knob 83 with their fingers, so that the cutting blade 81 will move toward these two auxiliary rollers 82. Then, the pipe 91 can be clamped. The user still needs to rotate the knob 83 tighter to force the cutting blade 81 feed in. After which, the user can rotate this entire mini-tube cutter to cut the pipe 91. A resilient element 84 can also be included. However, rotating the knob 83 one rotation, only moves the cutting blade 81 a very small distance. If the diameter of pipe 91 is small, the user has to rotate the knob 83 multiple rotations (several rotations, more than ten rotations or even more), finally it will contact the pipe 91. So, its major disadvantage is that it cannot quickly clamp on the pipe 91 when the user prepares to cut it. In addition, when a non-professional user feeds in, it is quite possible to apply too much force on it so that the pipe 91 (especially a metal thin pipe) will be deformed or be destroyed. Once the pipe 91 is deformed, it becomes useless and cannot be used later.
Another traditional pipe cutter (such as British Patent Pub. No. GB 2309407) is illustrated in FIG. 2. When the user wants to cut a pipe or a tube, a resilient element 84 (or called energy-storing element) can create a pressing force so that the cutting blade 81 will feed in and then cut the pipe 91. However, if the size of the pipe to be cut is altered the user has to find another different-sized tube cutter to fin the corresponding size. Therefore it is troublesome to frequently change to different-size tube cutter every time. Thus from the above-mention two traditional tube cutters, it is known that the resilient element disposed with the cutting blade 81 or the auxiliary rollers 82 can achieve the function of automatic feeding.
The disadvantages of the above-mentioned devices can be summarized as follows:
[1] It cannot quickly clamp the pipe. One traditional method is to use fingers to rotate the knob 83. It is very slow and troublesome. The other traditional method is to select another different-sized tube cutter to fit a specific size. They cannot quickly clamp on the pipe.
[2] It is easy to damage the pipe by over-applying force. If the fingers rotate the knob 83, it makes the cutting blade 81 and the auxiliary rollers 82 to clamp on the pipe 91. Due to this kind of design, when a non-professional user operates it, it is very easy to apply too much force on it. So, this over-applying force will make the pipe 91 partially deform. Once the pipe 91 is deformed, it cannot return to its original shape (circular hollow pipe). Hence, the deformed pipe cannot be cut anymore and cannot be used again. Thus, due to such over-applying force, it is easy to damage the pipe by a non-professional user.
Furthermore, as shown in FIGS. 3 to 5, a conventional hand-held glue (such as silicon-glue) injector has a slight-tilted stopping device 72 disposed on a central rod 71. This stopping device 72 is a stopper 721 having a through hole 722. The central rod 71 passes through the through hole 722 of the stopper 721. A resilient member 73 presses against this stopper 721 and make it slightly tilted. It also keeps the stopper 721 at a position called locking position P1. At this moment, the edge of the through hole 722 contacts with the central rod 71 and limits the central rod 71. Actually, it only can move forward. And, it cannot move backward. However, if the user has pressed the stopper 721, this slightly tilted stopper 721 will move to another position called releasing position P2. Because its contacting friction decreases, the locking state is gone. The central rod 71 becomes a movable one without limitation. However, no one utilizes such simple one-way locking mechanism on a tradition tube cutter.